The present disclosure relates to air filters and filtering chambers. More particularly, embodiments disclosed herein relate to filter chambers for gas turbine engines and to methods and systems for determining the residual useful life of filter media.
Power generation equipment, such as a gas turbine engine, uses a large amount of intake air to support the combustion process. Impure air laden with dust particles, salt, and other types of contaminants, however, may damage the compressor blades, the turbine blades and buckets and other types of power plant equipment components via corrosion, erosion, fouling and the like. Such component damage or fouling may reduce the life expectancy and negatively affect the performance of the overall gas turbine engine.
To combat the effect of contaminants on gas turbine efficiency and reduce potential damages to the turbomachinery components, filtration systems are typically used to remove particulate matter from the intake air stream. These systems may feature filter media on the upstream side of a compressor in order to capture particulate matter before it reaches compressor and the combustor of the gas turbine engine. Although effective, during long periods of operation the filter media may become saturated with particulate matter, which subsequently obstructs or impedes the flow of air and creates a significant pressure drop between the upstream and downstream side of the filter media. Therefore, periodic cleaning of the filter may be necessary.
Reverse pulse cleaning systems are known in the art for removing particulate matter from saturated filter media. These systems typically have a nozzle downstream of the filter and connected to an air supply. Cleaning air is provided to the nozzle by the air supply. The nozzle generates a pressure sound wave that generates a vibration that shocks the filter media of the filter cartridge causing the dust fall. Exhausted filters can thus to some extent be cleaned without requiring dismantling and replacement. However, at some point in time filters must be replaced. Moreover, some kinds of filter media are not suitable for reverse pulse cleaning and must be simply removed and replaced with fresh filters once saturated with particulate matter.
In some cases replacement requires shutdown of the gas turbine engine for a considerably long time interval. In any event replacement of a filter arrangement is a complex maintenance operation, which should require careful programming. An estimation of the residual useful life of a filter arrangement would be of great assistance in suitably programming a maintenance intervention of this kind.
The behavior of the filter arrangement during time and thus its residual useful life depend upon a plurality of factors, not all of which can be measured or known. For instance, existing methods for estimating the residual useful life of filters require an accurate model of the degradation phenomenon and a number of difficult-to-measure or unknown parameters, such as the air flow rate, environmental data, etc. These methods additionally, hardly adapt to changing operating conditions. Additional difficulties are caused by the large variability of filter duration, which depends upon several factors, such as the operating conditions, the contaminants present in the air, the type of filter cartridges used, etc.
There is therefore a need for a method which provides an accurate and efficient estimation of the residual useful life of a filter arrangement.